The embodiments described herein relate generally to a detection technique for chemical substances, and, more particularly, to using reagents to detect contraband substances such as explosives, narcotics, pesticides, and chemical warfare agents by means of spectrometry. More specifically, the methods and systems include using gas-solid phase chemistry to chemically modify a substance of interest so that the substance can be vaporized and detected through an analysis of the substance.
Certain contraband substances—such as inorganic oxidizer salts—are used in formulations for homemade explosives (HMEs). Examples of classes of these explosives include compounds of nitrates, chlorates, perchlorates and permanganates. These compounds have very low volatility, which makes them difficult to detect by detection systems that rely on vaporization of the sample for detection. Examples of these types of detection systems include mass spectrometry (MS) and ion mobility spectrometry (IMS).
As such, in some instances, detection systems are unable to identify potentially dangerous substances because the substance is not able to be vaporized within the detection system. In other instances, substances with a high melting point can only potentially be detected if a desorber is ramped up to high temperatures that produce less than satisfactory limits of detection. Moreover, in such instances, an expensive trap material that can be stable at high temperatures is required and the analysis time is increased (in some instances up to over five times as much time is required).
There remains a need, therefore, for detection systems and methods that chemically modify a substance of interest such that it can be vaporized without increasing analysis time, using extreme temperature ramping and/or using expensive trap materials. The present disclosure achieves these benefits while reducing the exposure of both the user and passenger/cargo to dangerous chemicals and reducing power consumption of the total system.